1- Geometry construction

 A cylindrical "Bag" is sliced in concentric "Ring".
 "Ring" are registered as cellFlux scorers. 
 
 2- Physics list

 PhysicsList.cc defines only a geantino and a transportation process.
         	
 3- Primary generator
 
 One shoots randomly a geantino perpendicular to the input face,
 eg. parallel to z axis
  	
 4- Detector response

 One prints scorer response event per event.